Paper sized with a condensation product of a fatty amine and hexahydro-1, 3, 5-triacrylyl-s-triazine



United States Patent Ofiice 2,794,737 Patented June 4-, 1957 Lennart A.Lundberg and Walter F. Reynolds, Jr., Stamford, Conn., assignors toAmerican Cyanamid Company, New York, N. Y., a corporation of Maine NoDrawing. Application June 10, B54, Serial No. 435,917

13 Claims. (Cl. 923) The present invention relates to cellulosic webs,including paper, sized by a content of a condensation product of about 1to 2 mols of a long chain alkylamine with 1 mol ofhexahydro-1,3,5-triacrylyl-s-triazine, and processes for the manufactureof such webs. The invention includes webs sized by a content of suchmaterial in at least partially polymerized form.

The present invention is chiefly based upon the dis covery that thecondensation products of 1 or 2 mols of a long chain saturated fattyamine with hexahydro-l,3,5- triacrylyl-s-triazine, in the form of theirwater-soluble salts, are valuable sizing agents which are stronglycationic and substantive to cellulosic fibers dispersed in aqueousmedium, and that these materials act as sizing agents which greatlyincrease the water-resistance of the fibers having a content of the samewhen formed into paper, etc. It has been found that certain of thesecompounds perform the additional function of wet strength agents.

We have still further found that the condensation products referred tomay be partially polymerized while in aqueous dispersion, and that whenso polymerized they yield superior results when employed in the mannerdescribed.

The preferred sized paper of the present invention have i the followingcharacteristics.

1. They have good resistance to penetration by water and excellentresistance to penetration by ink and by aqueous sodium hydroxide andlactic acid solutions.

2. They have very nearly the same dry strength as comparable papercontaining none of the sizing material.

3. They have very substantial wet strength, and this strength isincreased by contact with hot alkali solutions.

4. These properties are not significantly affected by the pH at whichthe cellulosic fibers are sheeted. The paper may thus contain withoutsubstantial detriment alkaline fillers such as calcium carbonate, or beused as material for the packaging of alkaline material such as cementor plaster.

The cellulosic webs of the present invention, broadly, are made by aprocess which includes the steps of contacting cellulosic fibers with anaqueous dispersion of the sizing materials referred to in eithermonomeric or partially prepolymerized form, depositing an effectiveamount on the fibers, and heating the fibers to dry the same and developthe sizing properties of the sizing agent thereon. During this heating,polymerization may take place depending on the presence or absence of acatalyst.

Sized webs of the present invention may be prepared by the tub-sizingmethod in which a preformed cellulosic web is immersed in or sprayed orpadded with a dilute (1%-5 aqueous dispersion ofv the sizing material,after which the web is dried by heating.

The webs may be more conveniently prepared by the beater additionmethod, this method taking advantage of the strongly cationic,cellulose-substantive characteristics of the sizing material. Accordingto this method, a dilute dispersion of the size is added to an aqueouscellulosic fiber suspension, which may have a pH between 4 and 9.

Adsorption is rapid, a sufliciently eifective amount usually beingadsorbed within about 1 minute and often within a few seconds. Thefibers are then sheeted to form paper or other web. Development of thewater-repellence and wet strengthening properties of the sizesubstantially takes place when the web is heated for about one-halfminute at 260 F. or 3-10 minutes at about 200 F.

Alkaline filled paper may be manufactured by adding calcium carbonate orother alkaline filler after addition of the resin to the aqueous fibroussuspension.

In some instances as little as 0.1% of the size material, based on thedry weight of the fibers, has imparted a noticeable amount ofwater-resistance, and the addition of this amount is therefore withinthe scope of the present invention. Much better results are obtainedwhen about 0.5% is added, this amount being considered about the minimumneeded for useful results in the absence of other sizing agents. BestWater-resistance per increment of sizing material added is obtained inthe range of about to 2% and larger amounts produce only a minorincrease in wet strength. However, up to about 4%5% may be added withcontinued and substantial increases in wet strength.

The sizing materials are conveniently prepared by a process whichcommences with heating between about 1 and 2 mols of a long chainsaturated fatty amine with hexahydro-1,3,5-triacrylyl-s-triazine, amethod for the preparation of which is disclosed in U. S. Patent No.2,559,835.

The condensation products containing 1 mol of fatty amine are preferred,since this group of compounds usually gives best sizing results and wetand dry strength.

Preferably, the amines referred to are long chain saturated fattyamines, that is, alkylamines containing 16-22 carbon atoms, the waterrepellence afforded decreasing rapidly when chains of shorter length areemployed, and the dispersibility of the addition products, even in theform of their salts, being unduly difficult in the case of chains ofgreater length. In practice, we prefer to use o'ctadecylamine, thismaterial being readily available while yielding a product whichdisperses readily while providing satisfactory water-resistance.Unsaturated fatty amines are tolerated well in small amounts and thusthere may be used the commercial, not quite completely hydrogenatedamines derived from naturally-occurring fatty acids containing up toabout 10% of unsaturated material.

The condensation products, after removal of any sol vent present, arenormally waxy solids, and are conveniently made into a size by grindingto a powder and slowly pouringthe powder into a volume of rapidlyagitated hot water containing suflicient of a lower watersoluble acid toform a fluid dispersion or suspension containing up to about 15% of theproduct as an amine salt thereof, beyond which concentration thedispersion is very viscous. It is preferred that less of thecondensation product be added so that the dispersion is quite fluid.Ordinarily, about 1 mol equivalent of acid is employed per mol ofcombined long chain amine, but often a lesser amount has provedsatisfactory while an excess does no harm. As acids, chloroacetic(mono-, di-, or tri-), formic, hydrochloric, glycolic, and propionic maybe used. Acetic acid is preferred, this acid being non-toxic, readilyavailable, and appearing to yield salts of the lowest softening point.

The dispersions thus formed, when diluted, exhibit the opalescent bluishhaze indicative of the presence of colloidal material therein, and maybe employed without further treatment in the manufacture of paper. Moreadvantageously, however, the dispersions are subjected to a'preliminarypolymerization. This is most conveniently done by treating thedispersions, hot or cold, with a small amount of any of the organiccatalysts heretofore known to promote vinyl polymerization. t-Butylhydroperoxide, peracetic acid, methyl ethyl ketone peroxide, performicacid, and the like are suitable, but because of its freedom from colorand lack of toxicity, we prefer to use hydrogen peroxide which yieldsentirely satisfactory results. Catalysts of the inorganic salt type areless convenient since these acts quite rapidly and tend to cause thedispersions to flocculate or gel in a comparatively short time.Completion of the action of the catalyst and therefore of thepolymerization occurs when the dispersions cease increasing inviscosity, this, in the case of hydrogen peroxide, usually requiringfrom about 30 minutes to 24 hours depending on the temperature,concentration of the dis persion, and the amount of catalyst added. Itis unnecessary to wait for termination of the pre-polymerizationreaction, excellent results having been obtained when the material hasreacted to a roughly estimated of completion. The dispersions are bestadded to the cellulosic fiber suspension before they have entered thegel stage or have flocculated, depending on the effect of the particularcatalyst used.

The effect of this pre-polymerization is to increase the size andcationic strength of the particles, as a result of which paper and othercellulosic products are obtained having greater wet and dry strengthwithout increase in the temperature or duration of the curing step.

A particular advantage associated with hydrogen peroxide as catalyst isthat only a very small amount is efiective and the use of a very largeamount is not accompanied by any serious detriment. Moreover, it actswith sutficient rapidity at room temperature. Thus, as little as 5%based on the weight of solids in the dispersion has been verysuccessfully, and the addition of 20% has given substantially identicalresults, 24 hours of standing being allowed in each instance so as topermit the catalytic action of the hydrogen peroxide to becomesubstantially fully evident. Only a negligible decrease in dry and wetstrength and water-resistance was observed in the paperproduced when 20%of hydrogen peroxide was added based on the weight of size solids with astanding time of five days. Moreover, in one experiment handsheets weremade from the dispersion of Example 1 without peroxide addition and fromdispersion of the same material containing 20% of hydrogen peroxide onthe weight of the size therein, handsheets being made five minutes, onehour, three hours, six hours, and 24 hours after addition of thehydrogen peroxide. The sheets were tested for their dry and wet tensilestrength and water-resistance by the Currier test, and ink-resistance bythe BKY test, and the sheets were formed at pH values of 5.0 and 9.0.With hydrogen peroxide at room temperature, the properties of thematerial as sizing agent were substantially completely developed at theend of one hour of standing or perhaps somewhat earlier. Thus, itappears that hydrogen peroxide is incapable of causingoverpolyrnerization under normal conditions. With other and more activecatalysts the dispersions should be used before evidence of flocculationor gelation appears.

The invention will be further illustrated by the examples which follow.These examples are preferred embodiments of the invention and are not tobe construed as limitations.

Example 1 was obtained which was crushed and oven-dried under vacuum at50-55 C. for six hours. The product was 1,3 diacrylylhexahydro-S-octadecylaminopropionybstriazine or a low molecular weighthomopolymer thereof.

Example 2 The procedure of Example 1 was repeated using 128 g. (0.516mol) of hexahydro-1,3,S-triacrylyl-s-triazine, 291 g. of octadecylamine(1.03 mols), and 800 cc. of ethylene dichloride. The product contained 2mols of combined octadecylamine per mol of the triazine taken. Theproduct was hexahydro 1 acrylyl-3,5-(octadecylaminopropionyl)-s-triazineor a low molecular weight homopolymer thereof.

Example 3 A series of papers was prepared as follows to illustrate theeffect of varying the number of mols of combined octadecylamine, theeffect of partial pre-polymerization, the amount of condensation productadded, and the pH of the fibrous suspension.

Sizing dispersions were made by grinding the products of Examples 1 and2, respectively containing 1 and 2 mols of combined octadecylamine, andslowly pouring the powders into water at C. containing 1 mol of aceticacid per mol of combined octadecylamine present. Two viscous dispersionswere obtained, each of which contained 2.25% solids. The dispersionswere divided into portions and these were used either without modification or after pro-polymerization with hydrogen peroxide as shown inthe table below. In the case of the dispersion formed from the productof Example 1, pre-poly' merization was effected by allowing theperoxide-treated dispersion to stand for 2 hours at roomtemperature. Inthe case of the dispersion formed from the product of Example 2, 3 hoursof standing was allowed.

In each instance the dispersions were stirred into 0.6% consistencybleached 60% su1fite-40% soda blended pulp suspensions which had beenbeaten to a Green freeness of 475ml. After addition of the dispersion,the pH of the suspensions was adjusted to the values shown in the tableby the use of. hydrochloric acid or sodium hydroxide as necessary,gently stirred for five minutes, and sheeted on a Nash handsheetmachine. The sheets were dried for one minute at 240 F. without blotter,conditioned for 24 hours at 72 F. and 50% relative humidity, and testedas shown in the table below.

Tensile Percent Percent Strength, BKY No. 11 0 Size pH of Basis Lb./in.Currier Ink Added Added 1 Stock 3 Wt. Sec. Sec. To Size 1 Dry Wet;

1---- Control Nil 46.0 17.8 I 0. 2 3 3 Product of Example 1 2. Nil 5.04. 5 46. 0 9. 3 1. 4 18 600 3. Nil 5. 0 9.0 46. 6 8. 7 2. 8 56 600 4--..10 5.0 4. 5 46.0 11. 9 2.7 54 600 5-. 10 6. 0 9. 0 46. 2 12. 4 2. 9 55(600 6- 10 2. 5 4. 5 48. 1 13. 9 3. 8 60 (600 10 2. 5 9. 0 47. 3 14. 62. 9 48 600 8...- 10 1. 25 4. 5 47. 3 15. 1 2. 3 50 600 9---. 10 1. 259. 0 47. 0 15. 7 1. 6 23 Product of Example 2 10... N11 5. 0 4. 5 45. 26. 2 1. 4 54 600 Nil 5. 0 9. 0 44. 9 5. 4 1. 8 56 600 12. 10 5. 0 4. 545. 2 5. 9 1. 2 51 600 13... 10 5.0 V 4. 5 44. 9 5. 1 1. 7 61 600Example 4 The manufacture of sized paper by the tub-sizing process usinga sizing material prepared from the product of Example 1, showing theefiect of the peroxide treatment is illustrated by the following.

A set of sulfite-soda handsheets having a basis weight of 48.0 lbs. andcontaining no added material whatever were impregnated with aqueousdispersions at various dilutions of the product of Example 1 at pH 4.5,prepared according to Example 2 without the use, of hydrogen peroxide.The sheets were squeezed to remove excess liquid and were estimated tocontain by weight of sizing solids. One of the sheets was set apart asprimary control and air-dried without further treatment. A second sheetwas impregnated with plain water at pH 4.5 as secondary control anddried at 240 F. for 1 minute on a laboratory drum dryer. The threeremaining sheets were air-dried and impregnated with aqueous hydrogenperoxide to absorb hydrogen peroxide in amounts shown in the tablebelow. The three test sheets were dried in the same manner as sheet No.2; the size thus being cured in the presence of hydrogen peroxide. Thedry tensile strength and water-resistance (Currier) of the sheets werethen determined with the following results.

The table shows that while good sizing was obtained (No. 2) without useof hydrogen peroxide, much better results were obtained when the sizewas cured in the presence of hydrogen peroxide.

Example 5 The following papers were made to illustrate the extraordinarylactic acid-resistance imparted by the size. The sizing materialemployed was prepared by adding 20% of hydrogen peroxide (as a 30%aqueous solution) to a 4.70% aqueous dispersion of the product ofExample 1 made by the use of acetic acid, and allowing the mixture tostand for 3 hours at room temperature. The suspension employed w!asbleached northern kraft pulp beaten to a Green freeness of 485 ml. anddiluted to 0.6% consistency. After addition of the size, the suspensionswere adjusted to pH 5 or 9 as shown in the table below, and stirred forfive minutes. The sheets were made according to the method of Example 3,except that they were dried for 3 minutes at 240 F. because of theirgreater thickness. The water-absorption test was made by the totalimmersion method and the lactic acid test by applying a 20% aqueoussolution of lactic acid to one side of the sheet and noting the timerequired for the solution to pass through at 100 F.

1 For explanation, see previous table.

Similar untreated paper absorbs 100% or more of its weight of water, andis instantaneously saturated by lactic acid.

Example 6 The following illustrates the resistance of sized paper of thepresent invention to boiling water, acid, and

Sized handsheets were prepared at a basis weight of about 48 lbs. frombleached northern kraft pulp employing the hydrogen peroxide treatedacetate dispersion of Example 5. The sheets were dried for one minute at240 F. and strips cut from each. The strips were aged at roomtemperature and their dry tensile strength values determined. Inaddition, one set of strips was boiled in 5% sodium carbonate solution,and another set in 2% sulfuric acid for 10 minutes each. The wet tensilestrength of these strips was then determined. Results were as follows:

Tensile Wet Tensile After- Percent Basis WtJ Size Added I Stock pH DryW6C N 800; H180 Boll Boil Nil 44. 7

encore comma 1 For footnotes, see previous table.

The data show that the alkali boil tended to increase the wetrstrengthof the paper, while appreciable wet strength remained after the acidboil.

What we claim is:

1. A cellulose web comprising water-laid cellulose fibers sized by acontent of from 0.1% to 5% of their dry weight of a condensation productof about 1 to 2 mols of a long chain saturated fatty amine wherein thechain contains 16-22 carbon atoms with 1 mol ofhexahydrol,3,S-triacrylyl-s-triazine.

2. A web according to claim 1, wherein the condensation product ispresent in at least partially polymerized form.

3. A cellulosic web comprising water-laid cellulose fibers sized by acontent of from 0.1% to 5% of their weight of a condensation product ofabout 1 mol of a long chain saturated fatty amine wherein the chaincontains 16-22 carbon atoms with 1 mol of hexahydro-1,3,S-triacrylyl-s-triazine.

4. A web according to claim 1, wherein the alkyl amine is octadecyiamine.

5. A web according to claim 1 containing from about 2% to 30% by weightof calcium carbonate filler.

6. A process for manufacturing sized paper which comprises contactingcellulosic fibers with a dilute aqueous dispersion of a salt of acondensation product of about 1 to 2 mols of a long chain saturatedfatty amine wherein the chain contains 16-22 carbon atoms with 1 mol ofhexahydro-1,3,S-triacrylyl-s-triazine, thereby depositing between about0.1% to 5% of said product on said fibers based on the dry weightthereof, and heating the fibers at about l90-260 F. for one-half to tenmin utes to dry the same and to develop the water-resistance propertiesof the condensation product thereon.

7. A process according to claim 6 wherein the dispersion contains thecondensation product in partially polymerized form.

8. A process for manufacturing sized paper which comprises forming anaqueous dispersion of cellulosic fibers, adding thereto an aqueousdispersion containing from about 0.1% to 5%, based on the dry weight ofthe fibers, of a salt of a condensation product of between about 1 and 2mols of a long chain saturated fatty amine wherein the chain contains16-22 carbon atoms with 1 mol of hexahydro-1,3,5-triacrylyl-s-triazine,thereby ad sorbing said condensation product on said fibers, sheetingthe fibers to form a cell-ulosic web, and heating the web at about 260F. for about one-half to ten,

minutes to develop the sizing properties of the condensation-productthereon.

9. A process. according to claim 8 wherein the condensation product isaddedin partially polymerized form.

10. A process according to claim 8 wherein the libers are sheeted at apH above 7.

11; A-process according to claim .8 wherein from about 2% to 30%of-calcium carbonate. filler is added to the suspension subsequent toaddition of the condensation product.-

12. A process according to claim 8 wherein the condensation product isthe addition product of about 1 mol of a long chain saturated fattyalkyl amine wherein the chain contains 16-22 carbon atoms with 1 mol ofhexahydro-1,3,5-triacrylyl-s-triazine.

13.- A process according to claim 8 wherein the alkyl amine isoctadecylamine.

References Cited in the file of this patent UNrrEp 4 STATES PATENTSBritt July 27, Schur Jan. 4, Sherman Nov. 15, Harrison et al. Apr. 11,Zerner et a1. July 10, Zerneret al. July 10, Daniel et a1. June 24,Zerner, et a1. Sept. 8, Daniel e t a1. Oct. 27, Lindqui st Feb. 11,Reynolds. y 6, Reynolds, Nov. 16,

OTHER REFERENCES MacDonald Paper Trade J.; April 11, 1929; page 54.

1. A CELLULOSE WEB COMPRISING WATER-LAID CELLULOSE FIBERS SIZED BY ACONTENT OF FROM 0.1% TO 5% OF THEIR DRY WEIGHT OF A CONDENSATION PRODUCTOF ABOUT 1 TO 2 MOLS OF A LONG CHAIN SATURATED FATTY AMINE WHEREIN THECHAIN CONTAINS 16-22 CARBON ATOMS WITH 1 MOL OFHEXAHYDRO1,3,5-TRIACRYLYL-S-TRIAZINE.